软启动照射模式对复合树脂聚合收缩的影响

Effect of soft-start curing mode on the polymerization shrinkage of resin composites

目的:测定不同光照强度的软启动照射模式下同一种复合树脂的聚合收缩率。方法:采用粘接片(bonded discs)法测定卡瑞斯玛光固化复合树脂(体积38.5 mm3,C值0.47)在不同照射模式(高普40 s、高普20 s、高渐进、高脉冲、中普、中渐进、中脉冲、台阶1、台阶2、台阶3)照射3 min的聚合收缩率。结果:3种台阶照射模式的聚合体积收缩率均显著大于其他照射模式(P<0.05);高普20 s模式的聚合体积收缩率显著大于高渐进、高脉冲模式(P<0.05),但与高普40s相比无显著差异(P>0.05);中普、中渐、中脉冲照射模式间体积收缩率两两相比均无显著差异(P>0.05);台阶1照射模式的体积收缩率显著大于台阶2和台阶3(P<0.05),而后两者无显著差异(P>0.05)。结论:光固化机固有的软启动和脉冲照射模式不能增加树脂的表面流动补偿收缩能力,应用光强更低的前期台阶照射模式则可显著增加树脂的表面流动补偿收缩能力。

AIM： To test the polymerization shrinkage of a resin composite light-cured with different softstart curing modes. METHODS ： The polymerization shrinkages of a resin composite （Charisma） were tested under ten light-curing modes using a bonded discs method： high continuous 40 s （800 mW/cm^2 40 s）, high continuous 20 s （ 800 mW/cm^2 20 s ） , high ramping （ 200 mW/cm^2 to 800 mW/cm^2 in 5 s ＋ 800 mW/cm^2 15 s）, high pulse （800mW/cm^2 20 s）, moderate continuous （400 mW/cm^2 40 s）, moderate ramping （200 mW/cm^2 to 400 mW/cm^2 in 5 s ＋ 400mW/cm^2 15 s）, moderate pulse （400 mW/cm^2 20 s）, two-step 1 （ 100 mW/cm^2 20 s ＋ 800mW/cm^2 20 s）, two-step 2 （200mW/cm^2 10 ＋ 800mW/cm^2 20 s） , two-step 3 （200mW/cm^2 20 s ＋ 800mW/cm^2 20 s）. RESULTS： The three two-step modes presented highest polymerization shrinkage （P 〈 0.05） and two-step 1 presented a higher shrinkage compared to two-step 2 and two-step 3 （P 〈 0.05） ; high continuous mode presented higher polymerization shrinkage than high ramping and high pulse（P 〈0.05 ） ; no significant difference was found among the three moderate modes （ P 〉 0. 05 ） ; no significant difference existed between high continuous 40 s and high continuous 20 s （P 〉 0.05 ）. CONCLUSION： The built-in ramping and pulse light-curing modes are unable to increase the pre-gel shrinkage of resin composite Charisma and a longer lower light intensity may increase the pre-gel shrinkage.